1. Field of the Invention
The present invention generally relates to sight glasses and more particularly to a sight glass where excessive sealing pressures are reduced and maximum visibility is obtained.
2. Description of the Prior Art
Typical industrial sight glasses have no provisions for controlling the absolute compression needed to seal the apparatus. The force applied for sealing is not controlled and during assembly, the glass can be exposed to many different amounts of force. Such force will unnecessarily subject the glass to excessive stress. Thus, weakening the glass before assembly.
Once assembled, the weakened glass is subject to the movement of the attached piping which can create an undesirable force resulting in glass breakage. Also after fitting, the weakened glass is subject to internal fluid pressure which could result in glass breakage.
Another problem with the typical industrial sight glass is that during fitting of the sight glass to the piping, there is no provision to prevent excessive tightening to achieve a water proof seal.